Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
854 am CST sun Feb 14 2016
issued at 854 am CST sun Feb 14 2016
Cancelled the Winter Weather Advisory a few hours early as the
main energy aloft is passing across Iowa at this time. Infrared satellite
imagery continues to show cloud top warming over our area. The
hrrr and hrrr-CR are also showing a diminishing trend to the snow.
There will be a northern stream short wave pass across central and
northern areas of Minnesota/WI this afternoon and evening and some light
snow will occur with this feature. Snow amounts up to an inch are
Short term...(today and tonight)
issued at 330 am CST sun Feb 14 2016
A potent wave over Nebraska and South Dakota continues to track east
southeast early this morning. It was strong enough Saturday evening
to produce quite a few thunderstorms across western South Dakota.
Cloud tops had been cooling on the northern end of the vorticity for much
of the night almost like a summertime mesoscale convective system...but that trend finally
appears to be reversing with the system beginning to shear apart as
the southern end accelerates to the southeast. Radar depictions of
the snow are gradually becoming less impressive near Aberdeen and
snow rates overall should be on the decline. In addition...there are
multiple bands or spokes spiraling out from the vorticity which has made
the snow more intermittent. These remnants will propagate across
southern Minnesota this morning with 1 to 3 inches expected. Will leave the
advisory in place for now and wait to see how things continue to
play out for the next few hours...especially with additional
development across northwestern Iowa. Areas north of I-94 may very
well be dry until this afternoon when the northern tail of the
elongated vorticity swings through. That may produce an inch into early
Long term...(monday through saturday)
issued at 330 am CST sun Feb 14 2016
The long term concerns remain the snow and possible mixed
precipitation moving across the area Monday night into Tuesday and
then the overall warming trend which should last into next
The deterministic models have been fairly consistent with another
short wave trough dropping southeast across the Dakotas and into
Iowa by Tuesday. System looks like it splits into two parts
..similar to the Sunday system. Will mention some likely probability of precipitation
over the far south late Monday night and continue the chance probability of precipitation
over the southeast into Tuesday. It does look like the best shot
of snow during this time. Warm air does lift into the southwest
ahead of the trough...and models indicate a possible mixed
sleet/snow/freezing rain scenario...at least for a time. We held
that threat over the southwest for now.
The system exits Tuesday afternoon should end the significant
precipitation threat until late in the week. Some cooling on the
backside of the wave for Wednesday...but ridging aloft follows...
along with warmer Pacific air. This should move into the area
with a warm front on Thursday night/Friday period. Ahead of the
front...will likely see low clouds and fog develop
Thursday/Thursday night as some higher dewpoints/melting occurs
over the snow pack. Temperatures are expected to warm above
freezing with some lower 40s likely Friday possibly lingering into
Saturday. The precipitation threat returns to the area Thursday
night and will continue Friday as the front/system moves through.
It appears much of the precipitation will be in the liquid
form...with some threat of freezing rain overnight as
temperatures drop off close to the freezing mark. Quantitative precipitation forecast amounts
associated dont look significant at the moment.
Aviation...(for the 12z tafs through 12z Monday morning)
issued at 617 am CST sun Feb 14 2016
Light snow has advanced into southern and western Minnesota where MVFR or
IFR conditions are in place. Elsewhere...dry air has slowed the
arrival of the snow and VFR conditions continue there. Eventually
the light snow will work its way further east...but expecting the
intensity to wane even more. Once the snow begins it will continue
occasionally for much of the day and even into the evening north
Kmsp...VFR conditions now but the snow should eventually work in
later this morning with MVFR conditions to follow.
/Outlook for kmsp/
Monday...MVFR/VFR ceilings. Wind west 10 knots.
Tuesday...MVFR/VFR with -sn possible. Wind northwest 10 knots.
Wednesday...VFR...lingering MVFR possible. Wind east-southeast 5 knots.